JoniB22 at 2013-08-27 15:54:58:
Plot. Always plot.
I tend to brainstorm in terms of WHO's and WHAT's, as in WHO is my main character and WHAT does he/she want? Then WHY does he/she want that and what's in the way of him/her getting it?
Then ... as I delve into what makes my character tick, I poke around into the core of the WHY. From there, usually but not always, a hint -- tiny or big, who knows -- about the story's theme will emerge. If it doesn't rear its head willingly, I'll mine for it. And I'll keep mining, off and on, until I find it.
While I'll push hard at the possibilities, plausibility and pitfalls of plot, I only nudge at theme. For me, plot seems to fall into the "work to be done" camp while theme is more "to be discovered".